The goal of the proposed project is to isolate and characterize several clones of tumor cells derived from a common parent. The parent tumor is a murine fibrosarcoma originally induced in a C57 b1/G mouse. Each clone isolated will be characterized with regard to the following in vitro properties: 1) growth rate, saturation density and anchorage dependence; 2) adhesiveness; 3) cell-cell aggregation and cell swelling; 4) random and chemotactic migratory activity; 5) invasion of chorioallantoic membrane cultures; and 6) content and release of hydrolytic enzyme. In addition to these in vitro parameters each clone will be characterized with regard to several parameters related to in vivo malignancy including tumorigenicity, in vivo growth rate and metastatic capability.